Developing Particle Control Infrastructure for the ESS High Beta Cavity Project Mark Pendleton – STFC Daresbury Laboratory Operating SRF systems reliably in a 'Dirty' machine_Mark Pendleton_140917

ESS High Beta Cavities STFC In-Kind Contribution: Niobium procurement Manage Eddy Current Scanning (DESY) Manage the Cavity fabrication of 84 + 4 high beta cavities in industry. Testing at STFC: 2K RF qualification of cavities to 22.9MV/m, Q0 ≥ 5 x 109 Transport to CEA Saclay.

Outline Design of the Cleanroom for ESS HB cavity re-work Modular Cleanrooms for Cryostat connections under ISO4 Conditions SPSV systems for the Cryostat + Cleanroom

HPR System Comments welcome: Commissioning and Validation. Processes and Procedures TBD Comments welcome: Commissioning and Validation. Monitoring during rinse cycle. Drying procedure - Including particle monitoring. Issues with filter systems. Drainage issues with UPW. System at CEA Saclay

Cryostat Insert Stand and Cleanroom facility requirements Structure to hold 2 Cryostat inserts 1500kg, laden ~1800kg (each) Personnel access for vacuum and electrical connections to be made on top of the cryostat. Access for cavity lifters to load and Unload cavities between the structure support legs. Framework to support a cleanroom solution. Access from the ground floor or office platform including escape route.

Cryostat Insert

Solution 1: Full Cleanroom enclosure Insert 2 Insert 1 Laminar Flow Unit Full enclosure Full enclosure Changing room Laminar Flow Unit Laminar Flow Unit Cleanroom 1 Cleanroom 2

Cryostat Insert Stand – Mock-up Laminar Flow Unit The mock stand has been built to determine a final working solution for the cryostat inserts and to develop a suitable cleanroom facility for the required operations. The mock stand has enabled the team to: Visualise the physical size and location of the structure. Determine the working height & position of the cavities, including testing the loading and unloading of cavities – including safe manoeuvrability of the cavity and clearance for the lifters. Design a cleanroom facility to meet ISO standards for the connection of the UHV lines. Determine processes and procedures. Changing room Cleanroom 1

Full Cleanroom Solution – Under test The cleanroom enclosure has been designed and built around the mock cryostat insert stand structure. Materials and equipment were sourced from previous projects, including: Anti-static perspex screens and seals. The main ULPA filtration fan unit. The floor has been cleaned but not sealed. Particle counts where taken at points 1 – 6. 10 x 1 minute air sampling taken at each position for 1m3 Points 1- 3 at cavity height 26” from the filter. Points 4 - 6 behind the UHV valve connection 1 4 Cavity 1 ISO 3 ISO 3 2 5 Cavity 2 ISO 3 ISO 3 3 6 Cavity 3 ISO 4 ISO 5 Laminar Flow Unit Best result: ISO 3 at rest Cleanroom 1

Solution 2: Glovebox The Glovebox solution has been designed to: Reduce the size of the cleanroom. Speed up the process, minimising cleaning of the cavity and infrastructure – reduced manpower. Eliminate the changing area and full gowning procedures. User friendly solution for enclosure/ isolation of the cavities. Reduce overall costs. Fixed particle counter monitoring for each cavity – quality control. Cavity 1 ISO 3 1 Cavity 2 ISO 3 2 Cavity 3 3 ISO 5 Laminar Flow Unit Best result: ISO 3 at rest Glovebox

Modular Cleanroom ISO 5 personnel Area and ISO 4 Isolator Seals around Cavity Flange Fixed particle monitoring for QA. Processes and procedures to be determined for UHV connection *Modelling performed by Connect 2 Cleanrooms

Modular Cleanroom

Cryostat Insert Stands Image 11/09/17

SPSV System System is fully automated except for manual cavity isolation valve RGA is used to check vacuum line (~10-7 mbar and leak rate ≤ 10-10 mbar∙l∙s-1 ) before cavity isolation valve is opened All cavities are expected to arrive under vacuum however system is designed so that it can tolerate an unforeseen high cavity pressure System allows both controlled venting and pumping using MFC’s Active pumping is stopped at approximately 70 K; system is then cryo-pumped. RGA monitors the cavity during cryopumping Active pumping re-started once RF test is complete and warm up begins Also Used for Quality Control/Acceptance test.

KEY: Backing Pump 1 Backing Pump 2 Backing Pump 3 N2 MFC N2 MFC N2 MFC PFV – Power Fail Valve L – Line V – Valve P – Pirani Gauge PRD – Pressure Relief Device FR – Full Range Gauge RGA – Residual Gas Analyser MFC – Mass Flow Controller SV – Separation Valve – Represents flow direction of MFC Backing Pump 1 Backing Pump 2 Backing Pump 3 L1V1 L2V1 L3V1 L1P1 L2P1 L3P1 L1P2 L2P2 L3P2 PFV1 PFV2 PFV3 N2 MFC N2 MFC N2 MFC L1P3 L2P3 L3P3 L1V3 Turbo 1 300 l/s L2V3 Turbo 2 300 l/s L3V3 Turbo 3 300 l/s L1V2 L2V2 L3V2 L1P4 L2P4 L3P4 MFC MFC MFC L1P6 L1CC1 L2P6 L2CC1 L3P6 L3CC1 L1P5 L2P5 L3P5 L1V5 L2V5 L3V5 L1CC2 L2CC2 L3CC2 L1V4 L2V4 L3V4 L1PRD1 L2PRD1 L3PRD1 L1P7 L2P7 L3P7 L1V6 L2V6 L3V6 SV1 SV2 L1PRD2 L2PRD2 L3PRD2 L1CC3 L2CC3 L3CC3 L1P8 L2P8 L3P8 L1 RGA1 L2 RGA1 L3 RGA1 L1V7 L2V7 L3V7 L1P9 L1CC4 L2P9 L2CC4 L3P9 L3CC4 CRYOSTAT TOP FLANGE

Discussion Main driver for transporting under vacuum? Acceptance criteria 10-4 mbar? To what standard have the SPSV systems been validated, including the UHV lines? Procedure if we have failures – full clean and particle count? RGA monitoring during testing?

Thanks to the ESS High Beta team Louis Bizel-Bizellot Phil R Davies Mike Ellis Philippe Goudket Ed Jordan Tom Jones Keith Middleman Peter McIntosh Shrikant Pattalwar Mark Pendleton Phill Smith Stuart Wilde